475LM Battery Back Up Sytem.
The LiftMaster 475LM Evercharge battery backup system from Garage Door Supply Company will operate your LiftMaster garage door opener when there's a power outage. The 475LM is a LiftMaster Elite Series Evercharge battery backup system that works only with LiftMaster garage door operator models 2500, 3500 and 3800. This backup battery will operate up to 20 full cycles in the event of a power failure.
An audible signal sounds when the door is operating under battery power. LED lights let you know when the backup battery is in use, when the battery is charging or when it's time to replace the battery. This is an easy-to-install LiftMaster garage door opener part. Mount it on top of or next to the opener. It plugs directly into your garage door operator.